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/cvs/liblzf/lzf_c.c
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Comparing liblzf/lzf_c.c (file contents):
Revision 1.16 by root, Mon Nov 5 23:28:40 2007 UTC vs.
Revision 1.22 by root, Tue Nov 13 10:41:52 2007 UTC

… …
45 * it works ;) 45 * it works ;)
46 */ 46 */
47#ifndef FRST 47#ifndef FRST
48# define FRST(p) (((p[0]) << 8) | p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
49# define NEXT(v,p) (((v) << 8) | p[2]) 49# define NEXT(v,p) (((v) << 8) | p[2])
50# if ULTRA_FAST
51# define IDX(h) (((h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
52# elif VERY_FAST
53# define IDX(h) (((h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
54# else
50# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) 55# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
56# endif
51/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/ 57/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
52#endif 58#endif
53/* 59/*
54 * IDX works because it is very similar to a multiplicative hash, e.g. 60 * IDX works because it is very similar to a multiplicative hash, e.g.
55 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 61 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
… …
68 74
69#define MAX_LIT (1 << 5) 75#define MAX_LIT (1 << 5)
70#define MAX_OFF (1 << 13) 76#define MAX_OFF (1 << 13)
71#define MAX_REF ((1 << 8) + (1 << 3)) 77#define MAX_REF ((1 << 8) + (1 << 3))
72 78
73#if (__i386 || __amd64) && __GNUC__ >= 3 79#if __GNUC__ >= 3
74# define lzf_movsb(dst, src, len) \ 80# define expect(expr,value) __builtin_expect ((expr),(value))
75 asm ("rep movsb" \ 81# define inline inline
76 : "=D" (dst), "=S" (src), "=c" (len) \ 82#else
77 : "0" (dst), "1" (src), "2" (len)); 83# define expect(expr,value) (expr)
84# define inline static
78#endif 85#endif
86
87#define expect_false(expr) expect ((expr) != 0, 0)
88#define expect_true(expr) expect ((expr) != 0, 1)
79 89
80/* 90/*
81 * compressed format 91 * compressed format
82 * 92 *
83 * 000LLLLL <L+1> ; literal 93 * 000LLLLL <L+1> ; literal
… …
102 u8 *op = (u8 *)out_data; 112 u8 *op = (u8 *)out_data;
103 const u8 *in_end = ip + in_len; 113 const u8 *in_end = ip + in_len;
104 u8 *out_end = op + out_len; 114 u8 *out_end = op + out_len;
105 const u8 *ref; 115 const u8 *ref;
106 116
107 unsigned int hval = FRST (ip); 117 unsigned int hval;
108 unsigned long off; 118 unsigned long off;
109 int lit = 0; 119 int lit;
120
121 if (!in_len || !out_len)
122 return 0;
110 123
111#if INIT_HTAB 124#if INIT_HTAB
112 memset (htab, 0, sizeof (htab)); 125 memset (htab, 0, sizeof (htab));
113# if 0 126# if 0
114 for (hslot = htab; hslot < htab + HSIZE; hslot++) 127 for (hslot = htab; hslot < htab + HSIZE; hslot++)
115 *hslot++ = ip; 128 *hslot++ = ip;
116# endif 129# endif
117#endif 130#endif
118 131
119 for (;;) 132 lit = 0; op++; /* start run */
133
134 hval = FRST (ip);
135 while (ip < in_end - 2)
120 { 136 {
121 if (ip < in_end - 2) 137 hval = NEXT (hval, ip);
138 hslot = htab + IDX (hval);
139 ref = *hslot; *hslot = ip;
140
141 if (1
142#if INIT_HTAB && !USE_MEMCPY
143 && ref < ip /* the next test will actually take care of this, but this is faster */
144#endif
145 && (off = ip - ref - 1) < MAX_OFF
146 && ip + 4 < in_end
147 && ref > (u8 *)in_data
148#if STRICT_ALIGN
149 && ref[0] == ip[0]
150 && ref[1] == ip[1]
151 && ref[2] == ip[2]
152#else
153 && *(u16 *)ref == *(u16 *)ip
154 && ref[2] == ip[2]
155#endif
156 )
122 { 157 {
123 hval = NEXT (hval, ip);
124 hslot = htab + IDX (hval);
125 ref = *hslot; *hslot = ip;
126
127 if (1
128#if INIT_HTAB && !USE_MEMCPY
129 && ref < ip /* the next test will actually take care of this, but this is faster */
130#endif
131 && (off = ip - ref - 1) < MAX_OFF
132 && ip + 4 < in_end
133 && ref > (u8 *)in_data
134#if STRICT_ALIGN
135 && ref[0] == ip[0]
136 && ref[1] == ip[1]
137 && ref[2] == ip[2]
138#else
139 && *(u16 *)ref == *(u16 *)ip
140 && ref[2] == ip[2]
141#endif
142 )
143 {
144 /* match found at *ref++ */ 158 /* match found at *ref++ */
145 unsigned int len = 2; 159 unsigned int len = 2;
146 unsigned int maxlen = in_end - ip - len; 160 unsigned int maxlen = in_end - ip - len;
147 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 161 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
148 162
149 if (op + lit + 1 + 3 >= out_end) 163 if (expect_false (op + 1 + 3 >= out_end))
150 return 0; 164 return 0;
165
166 op [- lit - 1] = lit - 1; /* stop run */
167 op -= !lit; /* undo run if length is zero */
168
169 for (;;)
170 {
171 if (expect_true (maxlen > 16))
172 {
173 len++; if (ref [len] != ip [len]) break;
174 len++; if (ref [len] != ip [len]) break;
175 len++; if (ref [len] != ip [len]) break;
176 len++; if (ref [len] != ip [len]) break;
177
178 len++; if (ref [len] != ip [len]) break;
179 len++; if (ref [len] != ip [len]) break;
180 len++; if (ref [len] != ip [len]) break;
181 len++; if (ref [len] != ip [len]) break;
182
183 len++; if (ref [len] != ip [len]) break;
184 len++; if (ref [len] != ip [len]) break;
185 len++; if (ref [len] != ip [len]) break;
186 len++; if (ref [len] != ip [len]) break;
187
188 len++; if (ref [len] != ip [len]) break;
189 len++; if (ref [len] != ip [len]) break;
190 len++; if (ref [len] != ip [len]) break;
191 len++; if (ref [len] != ip [len]) break;
192 }
151 193
152 do 194 do
153 len++; 195 len++;
154 while (len < maxlen && ref[len] == ip[len]); 196 while (len < maxlen && ref[len] == ip[len]);
155 197
156 if (lit)
157 { 198 break;
158 *op++ = lit - 1;
159 lit = -lit;
160 do
161 *op++ = ip[lit];
162 while (++lit);
163 } 199 }
164 200
165 len -= 2; 201 len -= 2;
166 ip++; 202 ip++;
167 203
168 if (len < 7) 204 if (len < 7)
169 { 205 {
170 *op++ = (off >> 8) + (len << 5); 206 *op++ = (off >> 8) + (len << 5);
171 } 207 }
172 else 208 else
173 { 209 {
174 *op++ = (off >> 8) + ( 7 << 5); 210 *op++ = (off >> 8) + ( 7 << 5);
175 *op++ = len - 7; 211 *op++ = len - 7;
176 } 212 }
177 213
178 *op++ = off; 214 *op++ = off;
179 215
180#if ULTRA_FAST || VERY_FAST 216#if ULTRA_FAST || VERY_FAST
181 ip += len; 217 ip += len;
182#if VERY_FAST && !ULTRA_FAST 218#if VERY_FAST && !ULTRA_FAST
183 --ip; 219 --ip;
184#endif 220#endif
185 hval = FRST (ip); 221 hval = FRST (ip);
186 222
223 hval = NEXT (hval, ip);
224 htab[IDX (hval)] = ip;
225 ip++;
226
227#if VERY_FAST && !ULTRA_FAST
228 hval = NEXT (hval, ip);
229 htab[IDX (hval)] = ip;
230 ip++;
231#endif
232#else
233 do
234 {
187 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
188 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
189 ip++; 237 ip++;
190
191#if VERY_FAST && !ULTRA_FAST
192 hval = NEXT (hval, ip);
193 htab[IDX (hval)] = ip;
194 ip++;
195#endif
196#else
197 do
198 {
199 hval = NEXT (hval, ip);
200 htab[IDX (hval)] = ip;
201 ip++;
202 } 238 }
203 while (len--); 239 while (len--);
204#endif 240#endif
241 lit = 0; op++; /* start run */
205 continue; 242 continue;
206 }
207 } 243 }
208 else if (ip == in_end)
209 break;
210 244
211 /* one more literal byte we must copy */ 245 /* one more literal byte we must copy */
246
247 if (expect_false (op >= out_end))
248 return 0;
249
212 lit++; 250 lit++;
213 ip++; 251 *op++ = *ip++;
214 252
215 if (lit == MAX_LIT) 253 if (expect_false (lit == MAX_LIT))
216 { 254 {
217 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
218 return 0; 256 lit = 0; op++; /* start run */
219
220 *op++ = MAX_LIT - 1;
221
222#ifdef lzf_movsb
223 ip -= lit;
224 lzf_movsb (op, ip, lit);
225#else
226 lit = -lit;
227 do
228 *op++ = ip[lit];
229 while (++lit);
230#endif
231 } 257 }
232 } 258 }
233 259
234 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
235 { 264 {
236 if (op + lit + 1 >= out_end) 265 lit++;
237 return 0;
238
239 *op++ = lit - 1; 266 *op++ = *ip++;
240#ifdef lzf_movsb
241 ip -= lit;
242 lzf_movsb (op, ip, lit);
243#else
244 lit = -lit;
245 do
246 *op++ = ip[lit];
247 while (++lit);
248#endif
249 } 267 }
250 268
269 op [- lit - 1] = lit - 1;
270
251 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
252} 272}
253 273

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